Commonly owned U.S. patent application Ser. No. 11/136,639, the entire disclosure of which is hereby incorporated by reference in its entirety, discloses shaft seal assemblies circumferentially extending about opposing ends of a rotor forming part of a hydrogen-cooled generator. Each shaft seal assembly comprises a sealing cartridge disposed in a bracket member. A sealing fluid is provided at an interface between the rotor shaft and each seal assembly to prevent the passage of gas through a gap at the interface.